1. Technical Field
The present invention relates generally to system and process for assembling camera modules.
2. Description of Related Art
Nowadays, digital camera modules are widely accepted for their ease of use, digital image storage, immediate results and image management potential. With respect to a related camera module, they generally include a lens module, a base member, and an image sensor fixed on the base member. The image sensor and the base member are located at an image side of the lens module. The image sensor is configured for detecting optical signals representative of a target image and converting the optical signals into electronic signals. The image sensor usually is a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) device. The lens module generally includes a lens barrel, a lens holder, at least a lens group, a spacer, and a filter (e.g., IR-cut filter). The lens group, the spacer and the filter are received in and arranged along an optical axis of the lens barrel. The lens holder defines an opening therein. An internal thread is defined on peripheral sidewalls of the opening. The internal thread is engaged together with an external thread of the lens barrel for thereby holding the lens barrel.
During the manufacture of the camera module, the at least one lens group, the filter, etc. are placed into the lens barrel and thereafter the lens barrel is threadedly coupled to the lens holder so as to form the lens module. Then, the lens module is mounted on the base member, thereby completing camera module assembly. Generally, before the lens module is mounted on the based member, there is a requirement for a center of the image sensor to be aligned with an optical axis of the lens module. A conventional method for meeting the above requirement is that of aligning the center of the image sensor with a center line of the lens barrel or a center line of an aperture opening of the lens barrel, based on an assumption that the center line of the lens barrel or the center line of the aperture opening is identical to an optical axis of the lens module. However, deviation between the optical axis of the lens module and the centerline of the lens barrel (or the center line of the aperture opening) inevitably exists, which results in an image quality of the camera module being degraded to some extent.
What is needed, therefore, is to provide system and process for assembling camera modules, thereby an optical axis of a lens module of an assembled camera module would be exactly aligned with a center of an image sensor of the assembled camera module.